Multi-ratio transmission

Abstract

A multi-stage transmission with eight forward and one reverse gear, including input and output shafts, planetary gearsets, gear stages, shift elements and shafts. Input shaft couples the carrier of gearset (P 1 ) and, via clutch ( 15 ), can couple shaft ( 5 ) that couples the ring and sun gears respectively of gearsets (P 2 , P 3 ). The ring gear of gearset (P 1 ) couples shaft ( 6 ), which couples the sun gear of gearset (P 2 ). Shaft ( 3 ) couples the sun gear of gearset (P 1 ), can couple the housing via brake ( 03 ), and can couple shaft ( 8 ), which couples the ring gear of gearset (P 3 ). The carrier of gearset (P 2 ) couples shaft ( 4 ), which can couple the output shaft ( 2 ) via gear stage (S 1 ) and clutch ( 24 ). The carrier of gearset (P 3 ) couples shaft ( 7 ), which couples gear stage (S 2 ), which couples the output shaft. A clutch ( 46, 56 or 45 ) can engage to block gearset (P 2 ).

The invention claimed is: 
     
       1. A multi-stage automatic transmission for a motor vehicle, comprising:
 an input shaft ( 1 ) and an output shaft ( 2 ); 
 first, second and third planetary gear sets (P 1 , P 2 , P 3 ), each of the first, the second and the third planetary gear sets comprising a sun gear, a ring gear and a carrier; 
 first and second spur gear stages (S 1 , S 2 ) being connected to a countershaft, disposed parallel to a longitudinal axis of the first, the second and the third planetary gear sets (P 1 , P 2 , P 3 ), serving as the output shaft ( 2 ) of the transmission, and the first and second spur gear stages (S 1 , S 2 ) being disposed inside a housing (G); 
 at least third, fourth, fifth, sixth, seventh and eighth rotatable shafts ( 3 ,  4 ,  5 ,  6 ,  7 ,  8 ); 
 at least five shift elements ( 03 ,  15 ,  24 ,  38 ,  45 ,  46 ,  56 ) comprising a brake ( 03 ) and first, second, third and fourth clutches ( 15 ,  24 ,  38 ,  45 ,  46 ,  56 ) which are selectively engagable to provide different transmission ratios between the input shaft ( 1 ) and the output shaft ( 2 ) such that eight forward gears and one reverse gear are implementable; 
 the input shaft ( 1 ) being connected to the carrier of the first planetary gear set (P 1 ) and connectable, by engagement of the first clutch ( 15 ), to the fifth shaft ( 5 ), and the fifth shaft ( 5 ) being connected to the ring gear of the second planetary gear set (P 2 ) and the sun gear of the third planetary gear seat (P 3 ); 
 the ring gear of the first planetary gear set (P 1 ) being connected to the sixth shaft ( 6 ) also being connected to the sun gear of the second planetary gear set (P 2 ); 
 the third shaft ( 3 ) being connected to the sun gear of the first planetary gear set (P 1 ), being connectable to the housing (G) of the transmission by engagement of the brake ( 03 ) and being connectable, by engagement of the third clutch ( 38 ), to the eighth shaft ( 8 ), and the eighth shaft ( 8 ) being connected to the ring gear of the third planetary gear set (P 3 ); 
 the carrier of the second planetary gear set (P 2 ) being connected to the fourth shaft ( 4 ), and the fourth shaft ( 4 ) being connectable to the output shaft ( 2 ) by the first spur gear stage (S 1 ) and the second clutch ( 24 ); 
 the carrier of the third planetary gear set (P 3 ) being connected to the seventh shaft ( 7 ) which is also connected to a first spur gear (ST 3 ) of the second spur gear stage (ST 2 ), and a second spur gear (ST 4 ) of the second spur gear stage (S 2 ) being connected to the output shaft ( 2 ); and 
 the fourth clutch ( 46 ,  56 ,  45 ) being engagable to block the second planetary gear set (P 2 ). 
 
     
     
       2. The multi-stage transmission according to  claim 1 , wherein the fourth clutch ( 46 ) detachably connects the sixth shaft ( 6 ) to the fourth shaft ( 4 ) and, when the fourth clutch ( 46 ) is engaged, the second planetary gear set (P 2 ) is blocked due to coupling of the carrier of the second planetary gear set (P 2 ) with the sun gear of the second planetary gear set (P 2 ). 
     
     
       3. The multi-stage transmission according to  claim 1 , wherein the fourth clutch ( 56 ) detachably connects the fifth shaft ( 5 ) to the sixth shaft ( 6 ), and when the fourth clutch ( 56 ) is engaged, the second planetary gear set (P 2 ) is blocked due to coupling of the sun gear of the secondary planetary gear set (P 2 ) with the ring gear of the second planetary gear set (P 2 ). 
     
     
       4. The multi-stage transmission according to  claim 1 , wherein the fourth clutch ( 45 ) detachably connects the fifth shaft ( 5 ) to the fourth shaft ( 4 ), and when the fourth clutch ( 45 ) is engaged, the second planetary gear set (P 2 ) is blocked due to coupling of the carrier of the secondary planetary gear set (P 2 ) with the ring gear of the second planetary gear set (P 2 ). 
     
     
       5. The multi-stage transmission according to  claim 1 , wherein the fourth shaft ( 4 ) is connected to a first spur gear (ST 1 ) of the first spur gear stage (S 1 ) and a second spur gear (ST 2 ) of the first spur gear stage (S 1 ) detachably connects the output shaft ( 2 ) by engagement of the second clutch ( 24 ). 
     
     
       6. The multi-stage transmission according to  claim 1 , wherein the fourth shaft ( 4 ) detachably connects a first spur gear (ST 1 ) of the first spur gear stage (S 1 ) by engagement of the second clutch ( 24 ), and the second spur gear (ST 2 ) of the first spur gear stage (S 1 ) is connected to the output shaft ( 2 ). 
     
     
       7. The multi-stage transmission according to  claim 1 , wherein the first, the second and the third planetary gear sets (P 1 , P 2 , P 3 ) are each configured as minus planetary gear sets. 
     
     
       8. The multi-stage transmission according to  claim 1 , wherein, from a radial perspective, the second planetary gear set (P 2 ) is disposed about the first planetary gear set (P 1 ). 
     
     
       9. The multi-stage transmission according to  claim 8 , wherein, from an axial perspective, the first, the second and the third planetary gear sets (P 1 , P 2 , P 3 ) are disposed in an order of the second planetary gear set (P 2 ) surrounding the first planetary gear set (P 1 ) to form a combined planetary gear set, and then the third planetary gear set (P 3 ). 
     
     
       10. The multi-stage transmission according to  claim 1 , wherein an electrical machine is provided that is either disposed on the input shaft of the transmission and directly connected to the input shaft, or is disposed axially parallel relative to the input shaft and connected to the input shaft by either a gear step or a chain drive. 
     
     
       11. The multi-stage transmission according to  claim 10 , wherein a fifth clutch is provided by which an internal combustion engine is decouplable from the transmission such that a totality of gears of the transmission are operatable by electrical means alone. 
     
     
       12. The multi-stage transmission according to  claim 1 , wherein,
 if the fourth clutch ( 46 ) detachably connects the fourth shaft ( 4 ) to the sixth shaft ( 6 ), then a first forward gear is implemented by engagement of the brake ( 03 ) and the first and the third clutches ( 15 ,  38 ), 
 a second forward gear is implemented by engagement of the brake ( 03 ) and the third and the fourth clutches ( 38 ,  46 ), 
 a third forward gear is implemented by engagement of the first, the third and the fourth clutches ( 15 ,  38 ,  46 ), 
 a fourth forward gear is implemented by engagement of the second, the third and the fourth clutches ( 24 ,  38 ,  46 ), 
 a fifth forward gear is implemented by engagement of the first, the second and the third clutches ( 15 ,  24 ,  38 ), 
 a sixth forward gear is implemented by engagement of the first, the second and the fourth clutches ( 15 ,  24 ,  46 ), 
 a seventh forward gear is implemented by engagement of the brake ( 03 ) and the first and the second clutches ( 15 ,  24 ), 
 an eighth forward gear is implemented by engagement of the brake ( 03 ) and the second and the fourth clutches ( 24 ,  46 ), and 
 the reverse gear is implemented by engagement of the brake ( 03 ) and the second and the third clutches ( 24 ,  38 ). 
 
     
     
       13. The multi-stage transmission according to  claim 1 , wherein, the fourth clutch ( 56 ,  45 ) either detachably connects the sixth shaft ( 6 ) to the fifth shaft ( 5 ) or detachably connects the fifth shaft ( 5 ) to the fourth shaft ( 4 ). 
     
     
       14. The multi-stage transmission according to  claim 1 , wherein at least one of a mechanical structural component, a belt, and a chain are disposed either instead of or additionally to at least one of the first spur gear stage and the second spur gear stage for transmission of torque. 
     
     
       15. The multi-stage transmission according to  claim 1 , wherein the output shaft ( 2 ) is connected to the input shaft of a differential by at least one planetary gear set. 
     
     
       16. A multi-stage automatic transmission for a motor vehicle, the transmission comprising:
 an input shaft ( 1 ) and an output shaft ( 2 ); 
 first, second and third planetary gear sets (P 1 , P 2 , P 3 ), each of the first, the second and the third planetary gear sets comprising a sun gear, a ring gear and a carrier; 
 first and second spur gear stages (S 1 , S 2 ) being connected to a countershaft, disposed parallel to a longitudinal axis of the first, the second and the third planetary gear sets (P 1 , P 2 , P 3 ), serving as the output shaft ( 2 ) of the transmission, and the first and second spur gear stages (S 1 , S 2 ) being disposed inside a housing (G) of the transmission; 
 at least third, fourth, fifth, sixth, seventh and eighth rotatable shafts ( 3 ,  4 ,  5 ,  6 ,  7 ,  8 ) 
 five shift elements ( 03 ,  15 ,  24 ,  38 ,  45 ,  46 ,  56 ) comprising a brake ( 03 ) and first, second, third, and fourth clutches ( 15 ,  24 ,  38 ,  45 ,  46 ,  56 ) which are selectively engagable to provide different transmission ratios between the input shaft ( 1 ) and the output shaft ( 2 ) such that eight forward gears and one reverse gear are implementable; 
 the input shaft ( 1 ) being continuously connected to the carrier of the first planetary gear set (P 1 ) and the input shaft ( 1 ) being connectable, via engagement of the first clutch ( 15 ), to the fifth shaft ( 5 ); 
 the output shaft ( 2 ) being continuously connected to the second spur gear (ST 4 ) of the second spur gear stage (S 2 ); 
 the third shaft ( 3 ) being continuously connected to the sun gear of the first planetary gear set (P 1 ), the third shaft ( 3 ) being connectable, by engagement of the brake ( 03 ), to the housing (G) of the transmission, and the third shaft ( 3 ) being connectable, by engagement of the third clutch ( 38 ), to the eighth shaft ( 8 ); 
 the fourth shaft ( 4 ) being continuously connected to the carrier of the second planetary gear set (P 2 ) and the fourth shaft ( 4 ) being connectable to the output shaft ( 2 ) via the first spur gear stage (S 1 ) and the second clutch ( 24 ); 
 the fifth shaft ( 5 ) being continuously connected to the ring gear of the second planetary gear set (P 2 ) and the sun gear of the third planetary gear seat (P 3 ); 
 the sixth shaft ( 6 ) being continuously connected to both the ring gear of the first planetary gear set (P 1 ) and the sun gear of the second planetary gear set (P 2 ); 
 the seventh shaft ( 7 ) being continuously connected to the carrier of the third planetary gear set (P 3 ) and the first spur gear (ST 3 ) of the second spur gear stage (ST 2 ); 
 the eighth shaft ( 8 ) being continuously connected to the ring gear of the third planetary gear set (P 3 ); and 
 the fourth clutch ( 46 ,  56 ,  45 ) being engagable for blocking the second planetary gear set (P 2 ).